In the field of microelectronics, electrostatic discharge can occur throughout the life of an integrated circuit, and is a real problem with respect to the reliability of this integrated circuit, as well as a major cause of failure.
In particular, an electrostatic discharge can arise during the fabrication stage for a circuit, when a person charged with static electricity handles the circuit. Upon contact with components, the static electricity discharges from the body of the person into the integrated circuit causing damage.
An electrostatic discharge generally results in a more or less significant and more or less short current peak.
Certain types of integrated circuits, such as, for example, radio-frequency integrated circuits including an antenna, include voltage regulating circuits connected to the terminals of the antenna providing for limiting possible voltage surges that may appear when the circuit is operating normally. Conventionally, these voltage regulating circuits include several transistors which become conducting when the voltage across the terminals of the antenna exceeds a certain threshold. Thus, the impedance at the terminals of the antenna is modified, and the voltage surge is absorbed.
However, it is necessary that these transistors remain blocked when an electrostatic discharge appears, since the currents generated are too high to be able to pass through the transistors without damaging them.
The use of several transistors notably means that one or other of the transistors can be blocked depending on the terminal which receives an electrostatic discharge, thereby providing a symmetric protection of the device.
However, the use of several transistors presents a drawback from the point of view of surface size. It is therefore proposed here to reduce this size.